Refactor: Frontend-Fundament — Format-Utils, Dialog-Ref, Typen (Phase 3a)

- Neuer lib/format.ts: gb/fmtBytes/fmtSize/fmtEta/fmtCtx zentral; aus
  DashboardView/SystemView/ModelsView entdoppelt und importiert.
- CustomDialog: document.getElementById -> useRef (kein DOM-Query, robuster).
- api.ts: GitInfo/ComponentVersion/Versions typisiert, SystemStatus.versions
  ergänzt; App.tsx nutzt SystemStatus statt any.

tsc grün, Build grün, Dashboard verifiziert (keine Konsolenfehler, Formatierer
rendern identisch).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/views/ModelsView.tsx

@@ -3,21 +3,10 @@ import { Download, Search, Trash2, Edit3, Star, Layers, Activity, HardDrive, X,
 import { api, type DiscoverResp, type Fit, type Job, type ModelInfo, type RoutingResp, type UpdatesResp, type ConnectResp } from "@/lib/api"
 import { CapsChips } from "@/components/CapsChips"
 import { cn } from "@/lib/utils"
+import { fmtBytes, fmtEta, fmtSize, fmtCtx } from "@/lib/format"
 import { CustomDialog } from "@/components/CustomDialog"
 
 
-function fmtBytes(b?: number) {
-  if (!b) return ""
-  if (b > 1024 ** 3) return `${(b / 1024 ** 3).toFixed(1)} GB`
-  return `${(b / 1024 ** 2).toFixed(0)} MB`
-}
-
-function fmtEta(s?: number) {
-  if (!s) return ""
-  const m = Math.floor(s / 60)
-  return m > 0 ? `${m} min` : `${s} s`
-}
-
 function JobsBar({ onError }: { onError?: (msg: string) => void }) {
   const [jobs, setJobs] = useState<Job[]>([])
   const [errorMsg, setErrorMsg] = useState<string | null>(null)
@@ -100,16 +89,6 @@ function JobsBar({ onError }: { onError?: (msg: string) => void }) {
   )
 }
 
-function fmtSize(b?: number | null) {
-  if (!b) return "—"
-  const gb = b / 1024 ** 3
-  return gb >= 1 ? `${gb.toFixed(1)} GB` : `${(b / 1024 ** 2).toFixed(0)} MB`
-}
-
-function fmtCtx(c: number | null) {
-  return c ? `${Math.round(c / 1024)}k` : "—"
-}
-
 function FitBadge({ fit }: { fit: Fit }) {
   const tone = {
     perfect: "bg-emerald-500/15 text-emerald-400 border border-emerald-500/20",